Figures 1A and 1B show ALT data obtained using the IR light emitter and IR video stream of a R200 Intel RealSense camera running at 60 frames per second rate for two distances of the R200 camera from a person sitting in an armchair in front of the R200 camera, as shown in Figure 2.
Figure 1A. corresponds to the distance of ~ 152 cm (60 in) between the camera and the backrest of the armchair:
Figure 1B corresponds to the distance of ~ 102 cm (40 in) between the camera and the backrest of the armchair:
ALT data in both Fig. 1A and Fig. 1B captured four full respiration cycles of the person.
Figure 2. A frame from the R200 camera's IR video stream.
Raw ALT data are shown in Figures 1A and 1B by gray lines connecting the data points. Black lines in Figures 1A and 1B are 24-points moving averages of the raw ALT data. As data in Figures 1A and 1B demonstrate, variations in the data related to heartbeats are less pronounced during respiration cycles in Fig. 1B compared to Fig. 1A. One can also say that relative contribution of the respiration into the ALT data increases with decreasing the distance between the person and the video camera and the light source elements (both elements are housed within the common enclosure of the R200 unit in this case).
Figures 3A and 3B show ALT data obtained using the IR light emitter and IR video stream of a F200 Intel RealSense camera running at 100 frames per second rate for two distances of the F200 camera from a person sitting on a chair in front of the F200 camera, as shown in Fig. 4.
Figure 3A corresponds to the distance of ~ 119 cm (47 in) between the camera and the backrest of the chair:
Figure 3B corresponds to the distance of ~ 81 cm (32 in) between the camera and the backrest of the chair:
ALT data in both Fig. 3A and Fig. 3B captured four full respiration cycles of the person.
Figure 4. A frame from the F200 camera's IR video stream.
Raw ALT data are shown in Figures 3A and 3B by gray lines connecting the data points. Black lines in Figures 3A and 3B are 20-points moving averages of the raw ALT data. As data in Figures 3A and 3B demonstrate, variations in the data related to heartbeats are less pronounced during respiration cycles in Fig. 3B compared to Fig. 3A. One can also say that relative contribution of the respiration into the ALT data increases with decreasing the distance between the person and the video camera and the light source elements (both elements are housed within the common enclosure of the F200 unit in this case).
As comparison of the data shown in Figures 1A and 1B, and 3A and 3B demonstrates, implementations of the ALT technology which use very different light textures generated by F200 and R200 RealSense cameras produce data exhibiting the same qualitative dependence on the distance between a person and the video camera and the light source elements of an ALT system.
ALT by Alexander Misharin, LVE Technologies LLC is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License. The full text of the CC BY-NC-SA 4.0 license can be found at https://creativecommons.org/licenses/by-nc-sa/4.0/legalcode. Contact LVE Technologies LLC if you would like to obtain a commercial license: info(at)lvetechnologies.com
